In 1992, more women (78.2 per cent) voted than men (77.2 per cent). But that number has been in decline ever since. In 2005 and 2010 there were more male voters than female. 64 per cent of women voted in the last general election, compared to 67 per cent of men.

Turnout has declined across both genders. But the drop is most significant in women. According to statistics compiled for the British Election Study – which were analysed by the Commons Library – the number of ‘missing’ female voters has risen by 79 per cent since 1992.

Between 1992 and 2010, the number of women voters in general elections fell by 18 per cent.

Harman announced the findings and made it clear that Labour intends to win over Britain’s absent women voters in this year’s general election by bringing "politics to the school gate and the shopping centre".

She also announced the publication of a ‘women’s manifesto’ to tackle issues such as childcare, domestic violence, equal pay and the representation of women in public life.

“Women are less likely to vote than men and the gender voting gap is widening. We believe that this election will be a watershed for women in this country,” she said.

"Politics is every bit as important and relevant to the lives of women as it is to men. Labour has set itself the challenge to make this case to the missing millions of women voters.

"There's been a lot of talk about Ukip or the SNP holding the balance of power. The reality is that the 9.1 million women who did not vote in the last general election will hold the balance of power and decide who walks into Number 10."

Both Ed Miliband and David Cameron have been accused of having a ‘women problem’ in the past.